Fuses, also referred to as blowing elements or as a one time programmable cell (OTP cell) are common elements for permanently storing data, such as serial numbers, trimming adjustments of analog circuits or the like, on a chip. When such a circuit is switched on, the data content stored in the fuses has to be read out via an analog signal and must be evaluated. The result is usually stored in a digital memory.
Apart from the fuse, conventional circuits comprise a comparison element, a comparator and a memory element. The condition of the fuse is determined on the basis of a difference in potential between the fuse and the comparison element. For reading out the condition of the fuse, a statically stable condition of the circuit has to be reached in order to obtain, and subsequently evaluate, a stable difference in potential and/or voltage. To this end, it is required to build the circuit in exact symmetry in order to balance any runtime differences caused by parasitic capacities, above all those of a blowing transistor usually needed for programming the fuse. In addition, it is required to defer the read-out of the condition of the fuse until the transient process, which is in the range of 100 nanoseconds, is finished.